Alkaline Paper Advocate

Volume 1, Number 5-6
Dec 1994


The ISR Research Proposal

A Summary, and Some Suggestions from the Advisory Committee

ASTM's Institute for Standards Research (ISR) issued a research proposal for paper permanence research around the first of November and invited applications from all labs willing and able to do the work. The project is called "Research Proposal to Study the Effects of Aging on Printing and Writing Papers." The application period is now closed, and one or more labs, out of the fourteen who responded, will be selected to perform the work.

The ISR is still looking for sponsors, contributors and subscribers to fund the research. The sponsors, who will provide the highest level of support, will receive full voting membership on the ISR Advisory Committee, quarterly updates of all research acivities and the final research report. They will approve the selection of a research contractor or contractors.

The contributors, at the next level of support, will receive semiannual updates of all research activities and the final research report. The subscribers will receive the semiannual updates.

Three sponsors had committed themselves by December 29. A New Sponsor Orientation meeting will be held March 1. Contracts will be awarded March 2 by the Advisory Committee.

Firms and organizations that are considering supporting this work may contact Kathleen Riley, ASTM Institute for Standards Research, 1916 Race St., Philadelphia, PA 19103 (215/ 299-5436, fax 299-5470).

An outline of a "Suggested Possible Subdivision of Research Work," by the advisory committee that sponsored the original workshop, follows this summary of the proposal.

Executive Summary

Research Proposal on the Effects of Aging on Printing and Writing Papers

Preamble. ASTM's Institute for Standards Research is undertaking a major research program to study the effects of aging of printing and writing papers. This need has arisen because of current lack of ability to predict the life expectancy of various papers with reasonable scientific certainty. As a consequence, many standards for papers requiring a degree of permanence are written with specific composition requirements or limitations. An alternate criterion for such standards would be that they be based only on the functional requirements of end users. While it is possible to establish such requirements and to test papers against them, there is insufficient scientific certainty that unaged papers will retain sufficient of their properties when they naturally age.

ASTM, through its Sub-Committee D6.50 on Paper and Paper Products Composition, has undertaken to determine the possibility of improving the needed scientific certainty by means of conducting relevant research on a prioritized basis. This work is being managed by ASTM's Institute for Standards Research (ISR).

As a means to identify the scope of required research, the ISR, with the support of twenty sponsoring organizations, conducted a workshop in Philadelphia from July 6-8, 1994. Over 100 people from 12 countries attended the workshop. It was attended by representatives from pulp and paper manufacturing companies; research institutions; libraries, archives and other end-user organizations; consultants; environmental organizations and other interested parties. The purpose of the workshop was to develop the objectives, scope and priorities for the proposed research program.

The participants in the workshop identified five key areas of focus. The first three are listed in the order of their priority:

  1. The development of credible, reliable test methods for the accelerated aging of paper that describe the aging procedures and the physical and chemical tests to be performed on the aged samples. Such test methods are to provide with expected precision, an estimate of the life expectancy of various papers that have met specified usage and storage conditions.
  2. The establishment of the probability with which the accelerated aging test methods predict the natural aging of printing and writing papers in the presence of any reasonable compositional variables.
  3. The identification of the important chemical and physical mechanisms which are factors in the natural and accelerated aging of paper, but are not yet fully understood.

A fourth area dealt with the optical [and] mechanical strength properties of printing and writing papers. The workshop discussions centered around the objective values and the limits of acceptability (LOA) for such properties, as well as for the attendant magnitude of loss of these properties that can be tolerated in documents that must last for long periods.

The "limits of acceptability" define the strength and other property points beyond which the paper is no longer functionally useful. Therefore, LOA's are the same for freshly made papers as for those that have experienced an aging process, however long that might be. Even though LOA's are included in all specifications for printing and writing papers, there may be a need for research to define additional limits for specific permanent papers. Such research is not intended as part of this program. If new or additional limits are shown to be required by paper users, a separate effort will be required. This would have to be launched under different funding. If there is a clear and present need for new or additional limits to provide guidance to this research program, every effort will be made to have them defined in time to provide timely input to the program.

The fifth area of focus dealt with the need to further perfect clear definitions for the terms "permanence" and "durability" so there can be broad agreement about such definitions within various communities where the words have relevance. It was agreed that this work is not an appropriate part of the proposed research, but rather, is an issue to be dealt with separately by ASTM. Upgraded terms will be proposed and submitted to ASTM Sub-Committee D6.01 on Paper and Paper Products Terminology for balloting, and input will be sought from those who attended the ISR workshop of July, 1994.

Purpose of Research

To conduct credible studies of the physical, chemical, and optical aspects of the aging of printing and writing papers that can specifically lead to standard test methods which functionally define the life-expectancy of such papers.

These studies will incorporate and consolidate the best existing knowledge of natural and accelerated aging processes, and the relationships between them.

In the event the research is successful, this effort is in support of development of ASTM standard test methods which will enable producers and users to specify paper permanence on the basis of functional performance rather than composition.

While this project is directed at the development of new standard test methods within the framework of and for the specific benefit of ASTM, it is hoped and expected thse research finding will be of benefit and use to other standards writing bodies around the world.

Technical Objectives of Research Program

  1. Proposals for predictive test methods to measure changes in optical and mechanical properties of paper upon aging in functional terms.
  2. Definition of knowledge gaps that prevent test method development.
  3. Proposals to eliminate such knowledge gaps.
  4. The research will consider at least:
  5. Accelerated aging studies will include evaluations of single sheets, stacks of sheets, and compressed stacks of sheets of paper in open and closed systems.
  6. Predictive methods will take into consideration the potential compositional ingredients of the range of current and reasonably expected future printing and writing papers. This included consideration of such possible components as polysaccharides, lignins, minerals, metal ions, and other contaminants and natural and synthetic polymeric additives. The methods should determine the individual and synergistic effects of such components on the aging of paper under a variety of conditions.
  7. Predictive methods will satisfy end user fundamental concerns regarding:
  8. Proposed research should contribute to a knowledge of which properties and the degree of change in properties that are relevant to predictive test methods for paper permanence. This may require consideration of data on historical papers subjected to long periods of natural aging that are now found in a wide range of conditions.
  9. Test Methods developed and or chosen will ultimately:
  10. The research results should describe the most desirable physical and chemical circumstances under which accelerated aging is to be performed.
  11. Because of the worldwide lack of well documented samples for natural aging studies, the research program should provide for a large set of papers to be placed in specified storage conditions for future research studies.
  12. A "pool" of very well documented papers is to be provided for use by all participants in this project.
  13. This research will fully utilize and not duplicate sound research that has been conducted at present throughout the world. Efforts will be made to correlate this research with some of the larger recent or ongoing studies, using some of the same samples, aging conditions, and tests, even if these are not deemed to be the definitive tests to use. "Sound" research is defined as that which has been so well documented that it can be repeated in other laboratories with the expectation of producing the same results and conclusions as were developed in the original work.
  14. If very old papers are utilized to establish a "naturally aged paper base," the most complete possible description will be provided regarding their composition, their conditions of manufacture, and the storage conditions that have prevailed throughout their life.

Suggested Possible Sub-Divisions of Research Work

I. Light Aging Test Method Development

Purpose

To develop an upgraded accelerated light aging test method in a way that correlates the brightness and color changes produced in the accelerated procedure with natural aging experiences so that end-users of measured papers will have reliable prediction of the time that will elapse until the papers have reached the allowable limits of brightness and color.

To additionally evaluate and define the potential for loss of mechanical and chemical properties of importance to users of the papers that are a result of the use of the test method. To relate the results of the accelerated procedure with natural light aging results, so that it will be known if procedure causes changes not expected during natural aging.

To endeavor to develop this light aging test method in a way that produces no change in paper properties other than those that will occur during natural aging under reasonable conditions of storage.

To develop this light aging test method in a way that is universally applicable to a wide range of reasonable combinations of composition variables in printing and writing papers.

Results Desired

  1. Specification of all information needed to produce an acceptable ASTM Test Method. (See "Form and Style for ASTM Standards," 8th Edition, September, 1989.)
  2. Correlation coefficients for the relationship between accelerated and natural aging rates of change of brightness and color.
  3. Identification of physical and chemical changes brought about in target papers by application of the light source. Identification of the relationship between these changes and those that occur during natural aging processes in which the paper is kept in reasonable conditions of storage.
  4. Provision of a test method that is universally reliable over a wide spectrum of printing and writing papers and that has been produced with any reasonable mix of compositional variables.

II. Heat/Humidity Aging Test Method Development

Purpose

To develop an upgraded test method that utilizes heat in the presence of humidity as a means to accelerate the aging of printing and writing papers. To ensure that the chosen method highly correlates the physical and chemical property changes produced in the accelerated procedure with natural aging experiences so that end-users of measured papers will have reliable prediction of the time that will elapse until the papers have reached the allowable limits of strength and other physical performance variables.

To endeavor to develop this test method in a way that produces no change in paper properties other than those thatwill occur during natural aging under reasonable conditrions of storage.

To develop this test method in a way that is universally applicable to a wide range of reasonable combinations of composition variables for printing and writing papers.

Results Desired

  1. Specification of all information needed to produce an acceptable ASTM Test Method. (See "Form and Style for ASTM Standards", 8th Edition, September, 1989.)
  2. Correlation coefficients for the relationship between accelerated and natural aging rates of change of relevant physical performance variables for the target papers. These variables are to include at minimum: MIT Fold Endurance, Tensile Energy Absorption, and Tearing Resistance.
  3. Identification of physical and chemical changes brought about in target papers by application of the heat and humidity sources. Identification of the relationship between these changes and those that occur during natural aging processes in which the paper is kept in reasonable conditions of storage.
  4. Provision of a test method that is universally reliable over a wide spectrum of printing and writing papers and that has been produced with any resonable mix of compositional variables.

III. Atmospheric Pollutant Aging Test Method Development

Purpose

To develop a new test method that utilizes sulfur dioxide (SO2) and oxides of nitrogen (NOx) separately and in combination as a means to accelerate the aging of printing and writing papers. To ensure that the chosen method highly correlates the physical and chemical property changes produced by the accelerated procedure with natural aging experiences that occur in reasonable storage environments.

This method should ensure that end-users of measured papers will have reliable prediction of the time that will elapse until the papers have reached the allowable limits of strength and other physical performance variables after exposure to concentrations of these pollutants that are likely to occur in reasonable storage environments.

To endeavor to develop this test method in a way that produces no change in paper properties other than those that will occur during natural aging in reasonable conditions of storage.

To develop this test method in a way that is universally applicable to a wide range of any reasonable combinations.

Results Desired

  1. Specification of all information needed to produce an acceptable ASTM Test Method. (See "Form and Style for ASTM Standards," 8th Edition, September, 1989.)
  2. Correlation coefficients for the relationship between accelerated and natural aging rates of change of identified important physical and chemical properties of the target papers.
  3. Identification of physical and chemical changes brought about in target papers by application of the atmospheric pollutants. Identification of the relationship between these changes and those that occur during natural aging processes in which the paper is kept in reasonable conditions of storage.
  4. Provision of a test method that is universally reliable over a wide spectrum of printing and writing papers and that has been produced with any reasonable mix of compositional variables.

IV. Physical and Chemical Mechanisms of Paper Aging

Purpose

To identify the important chemical and physical mechanisms which are factors in the natural and accelerated aging of paper, but are not yet fully understood. To, as fully as possible, describe the operation of these mechanisms under a full range of reasonable printing and writing compositional variables and of likely natural and accelerated aging conditions.

To conduct these studies in a way that differentiates major from minor effects and rank orders them in magnitude of influence on the changes that take place in the papers during aging.

To relate these findings to ongoing efforts to develop reliable accelerated aging test methods for this family of papers in a way that permits correlation between accelerated and natural aging processes and will permit other investigators to better determine whether or not accelerated aging methods create changes in the papers tha would not occur during natural aging in reasonable conditions of storage and use.

Results Desired

  1. A list of chemical and physical mechanisms studied, and justification as to why the list should be considered complete.
  2. A report that explains the operation of the mechanisms studied, and to the degree possible describes the equations by which these processes take place.
  3. A rank ordered listing of the relative importance of each of these mechanisms in both the natural and accelerated aging of printing and writing papers.
  4. An assessment of existing and developing accelerated aging test methods and an evaluation of which effects, if any, are likely to occur only during accelerated aging procedures.

Expected Accelerated Aging Test Methods

  1. Elevated temperature in the presence of humidity.
  2. Light. (To include at least the use of the xenon arc lamp with soda lime and borosilicate filters to simulate natural daylight passing through window glass, and fluorescent light to simulate light in interior building spaces.)
  3. The influence of atmospheric pollutants. (To include sulfur dioxide (SO2), oxides of nitrogen (NOx), and possibly ozone (O3).

V. Preparation of Papers for Printing and Writing Paper Aging Studies

Purpose

To prepare a very large quantity of papers for laboratory studies of the effects of aging on printing and writing papers in a way that so thoroughly documents the conditions of their manufacture that other suitably equipped laboratories in the world could reproduce identical paper samples. This work is required so that there can be no question regarding the ingredients and process of manufacture of these papers and so that sound, reproducible scientific studies can be undertaken through use of these papers.

To create facilities and to place quantities of the specially prepared papers in them for natural aging under controlled conditions over an extended period of time. Samples of these papers will be withdrawn from such storage facilities at regular intervals over a period of years to accurately document the changes brought about by natural aging.

Additionally, to prepare facilities for long term storage of quantities of the specially prepared papers in conditions which will lead to the least possible change of the physical and chemical properties of the papers over time. To place large quantities of the papers in these storage facilities for withdrawal at future dates to serve as a fresh supply of unchanged paper in future evaluations of natural and accelerated aging phenomena.

Results Desired

  1. Preparation of large quantities of printing and writing papers to be representative of the currently known array of such papers for use in scientific studies of natural and accelerated aging of such papers.
  2. Creation of facilities for the long term storage of large quantities of the specially prepared papers in conditions that are mutually agreed to represent reasonable storage for such papers that would be set aside for long term saving and use.
  3. Creation of facilities for the long term storage of large quantities of the speically prepared papers in conditions which would lead to the least possible change of the physical and chemical properties of the papers over time.
  4. Storage of quantities of these papers in the specially created facilities, continuing management of them under controlled conditions for future withdrawal by parties conducting scientific studies of the effects of aging on printing and writing papers.

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